multiple include files

[GE_Osmonics]

Hello:

Running into a lot of company written  #include files
where no protection is taken such as:

#ifndef __HEADERFILE_H
#define __HEADERFILE_H

blah, blah...

#endif

Files are included 2 and sometimes 3 times.
Strange part about this everything works properly.

Is CVI that smart that it figures out you only want one include?

[Alex D]

CVI does not do any work to guarantee than include files are only included once. There are even language reasons why we would not want to do this.

However, many redeclarations are legal and therefore many header files will probably compile fine even if included multiple times.

Struct declarations and enumerations will complain, but function prototypes and variable externs (for example) are ok.

Since many C API header files simply contain #defines and function prototypes, multiple inclusion will often still result in a successful (if slower) compile.

Hope this helps,

-alex